Dental matrix.



No. 765,084. PATBNTED JULY 12, 1904.

s. E. KNOWLES. DENTAL MATRIX.

APPLICATION FILED NOV. 5, 1902.

N0 MODEL.

Wimesses. inventor B-a'ILT,

UNITED STATES Patented July 12, 1904.

PATENT OFFICE.

DlENTALMATRIX.

SPECIFICATION forming part of Letters Patent No. 765,084, dated July 12,1904.

Application filed November 5, 1902. Serial No. 130,165. (No model.)

T0 all whom it may concern.-

Be it known that I, SAMUEL E. KNowLEs, a citizen of the United States,and a resident of the city and county of San Francisco and State ofCalifornia, have invented a new and useful Improvement in DentalMatrices, of which the following is a specification.

This invention relates to improvements in dental matrices such as areemployed in the operation of filling cavities with a plastic composition to furnish a temporary retaining-wall for the filling until thematerial has become set. The matrices provided for this purpose are madegenerally of a strip of thin sheet metal having the required pliabilityand of proper length to pass entirely around the tooth and bring theends in position to be seized and drawn toward each other by a clampingdevice of some kind. With the devices heretofore made, so far as I amaware, a mechanical clamp of suitable character to seize and draw theends of the band together is employed to draw the band around the toothand hold the same under the required tension, and as long as the matrixremains on the tooth the clamping device necessarily must be retained inthe mouth. In those constructions also wherein the matrix is directlyattached to the tension device by means of hooks or angular bends formedon the ends of the band the metal from which the band was made requireda certain degree of stiffness and thickness in order to prevent thehooks from straightening or bending outward under a strong tension. Inmy present improvement I produce a hook or angular bend on the end ofthe band that will stand all strain or tension that maybe thrown on theband even when the band is made of such soft and pliable material asGerman silver, and in connection therewith I provide a matrix that canbe drawn around a tooth and secured at any required tension by means ofdental floss, fine wire, or similar fastening means.

To such end and object my said invention consists in a hook or angularbend of novel construction on the end of the band or matrix, and in amatrix having oneach end a hook with a convex bearing-surface for afastening thread or wire, all as hereinafter fully described, andpointed out in the claims at the end of this specification.

In the following description reference is had by letters to theaccompanying drawings.

Figure 1 of the drawings is a side elevation of a cast of the lower jaw,showing my improved matrix and fastening on two teeth. Fig. 2 is aperspective view of the matrix bent to shape and before it is secured inplace. Fig. 3 is a view of a band or strip of narrow metal before it isbent to conform to the shape of the tooth on which it is to be placed.Fig. 4 is a band or strip to form a wide matrix and having two hooks oneach end.

That portion of the band a which is to extend around the side of thetooth where the lie in a vertical plane or perpendicular to the lengthof the band, I bend the fold or angle in an outward curve 0, that givesthe back of the recess or space a convex shape. The hook at its junctionwith the band then has substantially the shape seen in Figs. 2, 3, and4. The result of this construction is, first, to furnish a curved orrounded surface on which a thread f or a fine wire can be laid and drawnwith considerable degree of tensile strain without breaking, and,secondly, to form a hook that will not bend outward or straighten underany strain that will be brought to bear on the band' in the operation ofsecuring it in place on the tooth. This construction is of advantagealso in furnishing a surface that will not cut a thread when drawntightly against it, thereby enabling the. matrix to be secured in placeon the tooth by a few turns of dental floss or fine wire. This fasteningmeans being much simpler and more comfortable to the patient than themechanical clamp and tension devices heretofore used is equally aseffective and durable,

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enabling the matrix to be retained in position for a considerable lengthof time without discomfort to the patient and without interfering withor being displaced by the movements of the'jaws, lips, and tongue inperforming their accustomed functions. The construction is of advantage,furthermore, in enabling a strong and reliable hook to be formed on aband of soft and pliable material, thereby enabling a matrix to be madeof very thin and pliable metal capable of being inserted in confinedspaces between the teeth.

Having thus fully described my invention, What I claim as new therein,and desire to secure by Letters Patent, is-

1. As an improved article of manufacture a band of soft pliable materialhaving at each end a narrowed portion and each narrowed portion formedwith a hook, each hook bent back on the band and substantially in aplane therewith and having a convex face at the bottom of the recessbetween the hook and the band, said band being designed to serve as adental matrix and the convex faces of the hooks to receive the threadand prevent cutting thereof and the tendency to straighten out the hookby strain on the thread, as set forth.

2. As an improved article of manufacture, a dental matrix comprising aband of thin soft pliable material reduced in width at its ends andhaving at each end a plurality of separated hooks integral with the bandand bent toward each other with a convex face at the back of the recessbetween the hook and the band to receive a pliable fastening meansbearing on said convex face and prevent cutting of .said fasteningmeans, as and for the purpose set forth.

In testimony whereof I have signed my name in the presence of twosubscribing witnesses.

SAMUEL E. KNOWLES.

Witnesses:

EDWARD E. OSBORN, HARRY J. LAsK.

